Lubricating oil composition



Patented a. 21', 1939 v UNITED STATE sh PATENT-lorries I nunarcs'rme om oomosrrron Arnold' G. vob'unfwmung', Inn-as ignmto Sinclair Refining Company, New York, N. Y a corporation of Maine I No Drawing. Application-May 17', 1937..

- Serial No.143,121,

16 Claims.

My invention relates to improvements in compounded lubricating oils. The improved lubricating oil compositions of my invention consist essentially of a petroleum lubricating oil-having dissolved therein one or more metallic aromatic stearates, or metallic aromatic stearates together with metallic stearates, or metallic aromatic stearates or a mixture of metallic aromatic steare ates and metallic stearates together with an arcmatic stearic acid, stearic acid or palmitic acid.v

The addition of such soaps or soaps and free acid should be made in amount or amounts insuflicient materially to alter the normally liquid character of the petroleum lubricating oil itself, for example, from 0.5% to 2.5% on the oil.

Metallic aromatic ste'arates, which may be employed with great advantage to produce the improved compoundedlubricatingoil of the present invention; are the phenyl stearates of the following metals: Aluminum, barium, cadmium, chromium, magnesium and nickel. Examples of other metallic soaps, which are useful for the purposes 01! my invention, are the soaps of the above-mentioned metals and other aromatic stearlc acids such as, for example, tolyl steari c' acid,,xylyl stearic acid, naphthyl stearic acid and anthracyl stearic acid. The presence of an aromatic group in these metallic soaps seems to promote thesolvent capacity of the lubricating oil composi '30 tion with respect to sludge and may assist in improving its thermal stability. I have described and claimed lubricating compositions containing calcium aromatic steai'ates, or mixtures thereoi with calcium stearate or an aromatic stearic acid, in my co-pending application Serial No.89,120,'

' filed July 6, 1936, which has maturedinto United States Patent No. 2,081,075, datedaMay 18, 1937.

Calcium stearate has long been used in compounded petroleum lubricating greases. Thls in- 40 vention relates to improvements in'liquid petroleum lubricants as distinguished from solid. or

semi-solid petroleum greases and which containv soaps of metals other than calcium, The term petroleum lubricating oils" is intended'to refer ,5 herein to lubricating oils of petroleum origin having viscoslties upwards o! -40 seconds at 100 F. Saybolt Universal.

The trend of development in internalcombustion engines has imposed aincreasing burdens 50 upon the oils used i'or;their lubrication, particularly with respect to operating temperatures and pressures. At present, the Diesel type of engine probably represents extreme requirements in'both or these respects, but it is'not alone in the imposition of severe burdens upon the. lubricating resistance to oxidation, and the consequent te'nd ency to form sludge, but'ln another aspect'the effect of thermal instability is determinednot only by the extent of oxidation or decomposition 10 but also by the character of the products of such decomposition or oxidation and by the extent and location, within the engine, of-deposits of such products.

The improved lubricating oil compositions of l5 my inventionhave, in addition to the lubricating properties of the petroleum .oilsof which they are compounded, a high solvent capacity for jsludge, oi the character iormedby oxidation of petroleum lubricating oils and, perhaps ofeven go greater importance, the properties oi. rendering deposits of sludge and carbon within the engine soft and irlablerather than hard and co-' herent and of disintegrating and removing such 1 deposits as an incident of the normal operation 5 of the engine. In this aspect, the lubricating oil compositions or my invention render the engines in which they .are used self-cleaning to important extent. a c In' the Diesel typeo! engine, for example, the 30 -hlgh temperatures to which the lubricating oilis subjected, particularly at the top of the. stroke, frequently causes deposition of sludge and-carboniz'atlon in the groove for and behind one or more of the piston rings; Using paramnictype lubricating oils such dlfliculties are usually more 1 pronounced with respect to the uppermost ring; using naphthenlc type lubricating oil they are usually mo're'pronounced with respect tofithe' lower rings. Consequent, sticking of the rings 0 rapidly deprives the piston and cylinder wall of proper lubrication inducing excessive wear and,

,frequently, scoring of the cylinder wall. The formation of such carbon" deposits, hard enough and coherent enough to involve sticking of the rings, is materially retarded, ifnot avoided, by

' theme of the improved lubricatlngoil compositions of my invention,- and in this aspect thes'elfcleaning properties of the lubricating oil compositions of my invention, with respect to the en-- glne, make a mere change of oil a substitute, economical with respect both to lossof service timev and cost,'for many otherwise necessary cleaning and repairiobs. i

Metallic phenyl s'tearates, ormixtu'res includ- 55 sure and at ordinary temperature.

ates, for compounding the improved lubricating oil compositions of my invention, can be produced as follows:

1 part (parts by weight) of pulverulent anhydrous-aluminum chloride is stirred into 4 parts of commercial benzol boiling 90% below 100 C., this stirring being effected at atmospheric presmade over a period of about an hour. This re-- action is carried out at atmospheric pressure and is started at ordinary temperature. The temperature rise incident to the reaction is limited so that the'maximum temperature approximates 180-F., the temperature being controlled either by cooling or by regulating the rate of addition of the oleic acid. The reaction mixture is maintained at a temperature of 140-180 F. for 6 or '7 hours. For at least the last half hour of this period the reaction mixture is held at 180 F. to insure completionof the reaction and to assist in stripping hydrochloric acid from the reaction mixture. The reaction product, a pasty liquid, is then added to about to of its volume of aqueous hydrochloric acid, 15% to 20% HCl, at ordinary temperature. The ensuing reaction brings the temperature, for example, to about 170 F. This reaction mixture is thoroughly stirred and the aqueous acid solution is then separated from the oily product of the reaction, by decantation for example. This separated oily product is thoroughly washed with water, advantageously with hot water, in two successive stages with about of its volume of hot water in each stage for example. This washing should in any event be continued until a qualitative test for aluminum in the wash water is negative. After this washing, the reaction product is a thin, oily, dark green liquid. It is allowed to stand to settle out any remaining water. Benzol is stripped from this oily liquid by distillation, limiting the maximum liquid temperature to-about 350 F., using steam or other distillation medium to effect the stripping within this maximum temperature limit. The oily liquid' remaining after stripping of benzol is then subjected to distillation, advantageously under a high vacuum, 2-4 millimeters of mercury absolute pressure for example. This distillation may be otherwise effected, using steam or other distillation medium for example, provided the material undergoing distillation is not heated to any temperature muchexceeding 640-650 F. for any period long enough to involve decomposition. When effecting the distillation under a vacuum'of 4 millimeters of mercury absolute pressure, a first cut of about 25% is taken of! up to the point at which the temperature'of the liquid in the still reaches 466 F. and a second cut of about 53% is taken off as the temperature ofthe liquid in thestill rises from 466 F. to 590 F. The metallic phenyl stearates of the metals listed above with the exception of chromium which are used with advantage in the present invention may then be prepared from the phenyl stearicacid product contained in the above-described first and second fractions, or from phenyl stearic acid orphenyl stearic acid and stearic acid mixturesobtained from other sources, as

follows: 1 part ofphenyl stearic acid is completely saponiiied at temperature with the- 2 parts of ing metallic phenyl stearates and metallic steartheoretical quantity of 20 B. sodium hydroxide solution. When saponification is complete parts of water are added and the mixture stirred ,until the sodium phenyl stearate is completely dissolved; To this solution is then added a 1:6 solution of a soluble salt, acetate or nitrate of the metal whose phenyl stearate is desired. This salt solution is added in sufficient excess not only to precipitate but also. to coagulate the metallic phenyl stearate. The aqueous solution is decanted from the insoluble metallic soap, which is washed thoroughly withwater and dried by heating on a hot plate. In the preparation of the phenyl stearic soap of chromium, the just recited procedure is followed up to the point where the metallic phenyl stearate is precipitated. The nitrate or chloride is used as the precipitating agent. The further procedure is then to wash the chromium precipitate several times with water, disolve in suflicient benzene to give complete solution, filter, and remove the herein, I refer to the metallic soap constituting the major portion of the product resulting from the saponification and precipitation of the second distillate fraction from the condensation of oleic acid with benzol as described above although, of course, I intend to refer to this same material by whatever process it may be made. In referring to mixtures of metallic phenyl stearates and metallic stearates herein, I refer to a mixture of metallic soaps constituting the major portion of the product which results if the first distillate fraction as well as the second is saponified andprecipitated as an insoluble metal soap although, of course, I also intend to refer, by these terms, to these same materials by whatever process they may be prepared. I believe the metalic phenyl stearates, referred to, to be the metallic salt of 9-, or 10-phenyl, stearic acid, but I do not predicate my invention on this identification of the compound as a matter of terminology. The refractive indices, acid numduced as described in the preceding paragraph,

as determined in one-instance, wereas follows:

Total First Second reaction Residue product cut out I Refractive index at 20 O 1.4875 1.4610 1.4880 1. 5171 Acid num 166 193 127. 5 8a 168.1 192.6 161.7 I ine number 10 1.06 4.08 23.6

In compounding the improved lubricating oil compositions of rm! invention with the usual pe- 1 troleum lubricating oils, the metallic phenyl stearates, or the mixture-including metallic phenyl stearates and metallic stearates, as mentioned above, are added to the lubricating oil in pro- 7 portions ranging from about 0.5% up to about 2.0% or 2.5% by weight on the oil. A composition consisting chiefly of a South Texas pale oil having a viscosity of bolt Universal and boiling approximately 10% up 500 seconds at 100 F. Sayto 100 F. and 90% up to 900 F., and 1.3% by weight on the oil of a mixture of a phenyl stearate and a stearate of any one of the metals above described is particularly advantageous. Such a mixture of phenyl stearate 1 and stearate is advantageously made by saponifying together the first and second distillate fractions from the ,vacuum' distillation of the reaction mixture from the condensation o1 oleic acid with benzol as above described and then precipitating the desired insoluble metallic soap by adding the appropriate metal salt. test on a group of compounded compositions,

eachcontaining a diflerent one of the soaps of the recited metals, was 25-26 hours with the excep- ,ginesubstantially free from sludge or carbon deposits.

- The properties r these particular lubricating oils, as compared to the lubricating-oil alone, as determined in one specific instance for each of the compounded mixtures using 1.33% metallic phenyl stearates prepared according to the procedure above outlined arerecorded in the followa ing table:

f" metallic soap free from I s i m gems :1 mic on s eara South p .or- Texas oil . Alumi- Bar- Cadnum ium mium 524 544' ass 55 56.4 53. 2 l0 5 +5 183 134 033 As 123 297 119 Coke residue Bolt Bolt Soft Indiana sludge test .hours.- 13. 5 I 25 i6 22. 5

South Texas oil and 1.35%

south phenyl stearate oia g g Nickel 509 536 a "565 55. 7 54. 6 57. 4 --l0 'l0 10 .128 .100 .330 Ash 077 122 170 Coke residue Hard Soft Soft Soit Indians sludge test. '.hours- 13. 5 26 25 The metallic phenyl stearate in each of the blends to which the foregoing table of properties relates was a substantially completely saponified phenyl stearic acid, with the exception of the blend including the cadmium soap. Inthe case of the composition containing a,1ao,eo7

the cadmium soap, the compounding agent con:

The Indiana oxidation sisted'of 75% cadmium phenyl stearate and 25% free phenyl stearic acid.

tendency of any of the compounding agents above mentioned, abnormally to increase the viscosity of the oil to which it is added, may

be reduced by the addition of a small amount of iree phenyl stearic acid. In all of the above mentioned blends, with the exception of the blend including the cadmium soap, the addition of 7-8 of the acid, based on the soap, is effective for this purpose, although proportions up to about 20% are sometimes advantageous. For this purpose free stearic acid and free palmitic acid as I alone or with well as mixtures of these acids phenyl stearicacid, also are useful. While the lubricating oil compositions oi the foregoing examples embody specifically a South Texas lubricating oil, my invention is not limited to lubricating oil compositions embodying petroleum lubri-- v eating all ot-this specific origin.

I claim:

1. A liquid lubricating oil composition comprising a petroleum lubricating oil and a metallic phenyl stearate selected from the class consisting of the phenyl stearates of aluminum, barium, cadmium, chromium, magnesium and nickel.

2. A liquid lubricating oil composition com-- prising a petroleum lubricating oil, a metallic phenyl stearate selected from the class consisting of the phenyl stearate of, aluminum, barium, cadmium, chromium, magnesium and nickel, and a metallic stearate selected from ing of the stearates of aluminum, barium, mium, chromium, magnesium and nickel.

3, A liquid lubricating oil composition comprising a petroleum lubricating oil, a metallic phenyl stearate selected from the class consisting of the phenyl stearates of aluminum, barium, cadmium, chromium, magnesium and nickel, and phenyl stearic acid.-

4. A liquid lubricating oil composition comprising a petroleum lubricating oil, a metallic phenyl stearate selected from the class consisting of the phenyl stearates of aluminum, barium, cadmium, chromium, magnesium and nickel, ametallic ste'arate selected from the class consisting of the stearates of aluminum, barium, cadmium, chromium,:riagnesium and nickel, and phenyl stearicacid. I I 5. A liquid lubricating oil composition compriscading a. petroleum lubricating oil, a metallic phenyl the class consisting of the cadmium,

stearate selected from phenyl stearates of aluminum, barium,

- chromium,-magnesium and nickel,- and stearic acid.

6. A liquid lubricatingoil composition com-. prising a petroleum lubricating oil, a metallic phenyl stearate selected from the class consisting of the phenyl stearates of aluminum, barium, cadmium, chromium,

magnesium and nickel, and" the class consista fatty acid of the class consisting of stearic acid 01! the phenyl stearates of aluminum, barium,

cadmium, chromium, magnesium and nickel, a

' metallic stearate selected from the class consistmagnesium and nickel, and

- stearate selected from the class consisting of the stearates of aluminum, barium, cadmium, chromium, magnesium andnickel, and a fatty acid of the class consisting of stearic acid and palmitic acid.

10. A liquid lubricating oil composition comprising a petroleum lubricating oil and a metallic aromatic stearate selected from the class consist-u ing of the aromatic stearates of aluminum, barium, cadmium, chromium, magnesium and nickel.

11. A liquid lubricating oil composition comprising a petroleum lubricating oil, a metallic aromatic stearate selected from the class consisting of the aromatic stearates'of aluminum, barium, cadmium, chromium, magnesium an nickel, and an aromatic stearic acid.

12. A liquid lubricating oil composition comprising a petroleum lubricating oil, a metallic aromatic stearate selected from the class consisting of the aromaticstearates of aluminum, barium, cadmium, chromium, magnesium and nickel, and a fatty acid of the class consisting of stearic acid and palmitic acid.

13. A liquid lubricating oil composition comprising a petroleum lubricating oil, a metallic aromatic stearate selected from the class consisting of the aromatic stearates of aluminum, barium, cadmium, chromium, magnesium, and nickel, and a mixture of stearic acid and palmitic acid.

14. A liquid, lubricating oil composition comprising a. petroleum lubricating oil and magnesium phenyl stearate.

' 15. A liquid lubricating oil composition comprising a'petroleum lubricating oil and chromium phenyl stearate.

16. A liquid lubricating oil composition com prising a petroleum lubricating oil and aluminum phenyl stearate.

ARNOLD C. VOBACjH. 1 

